This invention relates generally to high-voltage insulators, and more particularly, to an arrangement for preventing the formation of a foreign layer on a high-voltage insulator by means of an air blast.
High-voltage insulators are known as being prone to arcing, particularly in areas where foreign substances which are contained in air are deposited on the insulators so as to form conducting foreign layers which are moistened by dew or fog. Wind and rain are a cleansing means by which the foreign substance layers can be removed naturally from the insulators. However, in situations where wind and rain are not available to perform the cleaning operation, the ability of the insulators to perform the insulating function is greatly limited. Consequently, the insulators will fail thereby producing disturbances in the distribution of power.
One known device for cleaning overhead power line insulators utilizes pressurized water. The known device consists of a pressurized water standpipe which is raised at the high-voltage tower and rotatably connected at a suitable height to a jet pipe which is movable in a vertical plane. The direction of the water jet can be controlled from the ground by swiveling and turning the standpipe. It is, however, difficult to divide the water jet into individual droplets to reduce the conduction of electric current through the water stream. Moreover, a substantial amount of equipment is required to bring the water to the desired location.
One known system which is particularly adapted for removing dust from horizontal feedthroughs of insulating material in high-voltage switching installation utilizes in its upper portion a plurality of nozzles for intermittently blasting the feedthrough with compressed air. The compressed air is obtained from the compressed air system which serves for operating the breakers. In this arrangement, the nozzles and the feed line are well grounded. However, although this system can be economically used in switching plants, such is not the case with high-voltage overhead lines.
It is, therefore, an object of this invention to provide an arrangement which can be used in open-air switching installations as well as in high-voltage overhead lines to prevent the formation of foreign layers on the high-voltage insulators.